For cosmetic purposes, colored contact lenses having one or more colorants dispersed in the lens or printed on the lens are in high demand. These colored contact lenses enhance the natural beauty of the eye, or provide unique patterns on the iris of the wearer, or provide non cosmetic patterns.
In general, there are two types of colored contact lenses. The first are contact lenses which use essentially transparent enhancement colors that allow the color of the natural iris to show through but combine with that natural color to produce a new appearance. Such tinted lenses are typically used to turn a light eye (e.g., green) to a slightly different hue (e.g., aqua). This class of colored lenses may not be able to change an underlying dark colored, brown iris to blue. The second category is the class of opaque colored lenses having a continuous opaque pattern that fully covers the iris or having an intermittent opaque pattern that does not fully cover the iris. Opaque colored contact lenses can effectively and substantially modify the wearer's eye color.
Over the years many attempts have been made to enhance the color of one's eyes using colored contact lenses with varying degrees of success (see, for example, U.S. Pat. Nos. 4,634,449, 4,954,132, 5,793,466). Generally, at least one of the following approaches have been employed in making colored lenses for color enhancement: (1) printing a solid color disk with a transparent or translucent reactive dye on both the pupil and iris sections of a lens; (2) printing a solid color ring with a transparent or translucent reactive dye or with a translucent pigment on the iris section of a lens; (3) printing a plurality of colored lines radiating out from a circle circumscribing the pupil section of a lens; (4) tinting a lens with a tinting agent in an edge-to-edge manner; and the like. Those colored lenses do enhance the eye color of the wearer, but they may also have one or more disadvantages as follows. First, they may not achieve the strikingly natural appearance desired in the industry. Second, complete coverage of the iris and pupil limits the amount of color intensity that the lens can impart on the iris without affecting the appearance of a colored filter in the visual field. Third, printing a solid disk or annular shaped object has often proved difficult in the past, since the ink coverage may cause lens warping. Fourth, printing in or near the optical zone of a lens, especially when print quality degrades, can affect visual acuity. Fifth, they may have noticeable printing boundaries between the iris section and other sections (e.g., the pupil section and the peripheral section).
Accordingly, there are still needs for colored contact lenses that can change the hue or color intensity enough to visibly see a difference compared to the natural iris while maintaining the underlying iris structure.